1. Field of the Invention
The present invention relates generally to hearing devices and, more particularly, to a hearing device having one or more in-the-canal vibrating extensions.
2. Related Art
Hearing loss is generally of two types, conductive and sensorineural. The treatment of both of types of hearing loss has been quite different, relying on different principles to deliver sound signals to be perceived by the brain as sound.
Sensorineural hearing loss is due to the absence or destruction of the cochlear hair cells which transduce acoustic signals into auditory nerve impulses. Individuals suffering from sensorineural hearing loss are unable to derive any benefit from conventional hearing aids due to the absence of, or damage to, the natural mechanisms that transduce sound energy into auditory nerve impulses. In such cases, cochlear implants have been developed. Cochlear implants provide electrical stimulation to the auditory nerve via stimulating electrodes positioned adjacent to the auditory nerve, essentially bypassing the hair cells of the cochlea. Application of an electrical stimulation pattern to the auditory nerve endings causes impulses to be sent to the brain, resulting in sound perception.
Conductive hearing loss occurs when the normal mechanical pathways for sound to reach the hair cells in the cochlea are impeded, for example, by damage to the ossicles. In such cases, hearing loss is often improved with the use of conventional hearing aids, which amplify sound. Such hearing aids utilize acoustic mechanical stimulation, whereby the sound is amplified according to a number of varying techniques, and is delivered to the inner ear as mechanical energy. This may be through a column of air to the eardrum, or through direct delivery to the ossicles of the middle ear.
One class of hearing device, referred to as air conduction devices, delivers the mechanical energy by delivering a column of air to the eardrum. Such air conducting devices work by collecting ambient sound with a microphone, amplifying the sound and delivering the amplified signal by way of a speaker positioned in the outer portion of the ear canal.
Another class of device, referred to as middle ear implants, delivers the mechanical energy by directly delivering the mechanical energy to the ossicles of the middle ear. Such middle ear implants work by collecting ambient sound with a microphone, processing the sound and vibrating a rod implanted adjacent to or fixed to a bone in the ossicular chain, or adjacent the oval window of the cochlea.
A further class of device, referred to as a bone anchored hearing aid, converts incoming sound into mechanical vibrations that are transmitted through the bone surrounding the otic capsule. The resulting bone vibrations stimulate the cochlea, resulting in a perceived sound. The direct bone conduction provided by a bone anchored hearing aid has been utilized as a treatment for conductive and mixed hearing losses (with a mild sensoneural component) as well as for the treatment of unilateral sensorineural hearing loss. Typically, a bone anchored hearing aid is used to help people with chronic ear infections, congenital external auditory canal atresia and single sided deafness, as such persons often cannot benefit from conventional hearing aids. Conventional bone anchored hearing aid devices are surgically implanted to allow sound to be conducted through the bone rather than via the middle ear.